York-class Cruiser
Overview
The First Contact War of 2157 was the first major test of the newly built Alliance Fleet. The war showed the Alliance how much of a technological disadvantage they had when compared to the newly discovered alien races. If they wanted to compete on the galactic stage, a massive fleet overhall was needed. With their increased political clout from earth, the Alliance managed to procure funding for Alliance R and D to develop a new generation of ships, with the help of data gathered during the war and the reverse-engineering of a "salvaged" turian Frigate, the Alliance retrofitted their Fleet to bring them to the same level as the turians and began designing a new 3rd Generation of warships designed to be superior in every way to their turian counterparts.
The first of these was the York-class Cruiser, named after the city of York and commissioned in 2160, three years after the First Contact war.
While the larger Dreadnoughts and carriers serve as the centerpiece of Alliance power projection and defence, Cruisers were the largest combat unit encountered away from major naval bases within Alliance space. Often escorted by Frigates.
During major naval battles, the Cruisers made up the main battle line, supporting and protecting the Dreadnought, while Frigates screened against smaller and more nimble units.
By 2186, York-class Cruisers made up 70% of Alliance Cruisers. Less than 20% of these ships would survive the Reaper war. Those that did would eventually be decommissioned within the following decade as new ships based on Reaper technology would completely outclass them.
Hull and Superstructure
The York-class features a long, thin hull built around it's main gun, flanked on either side by large, triangular wings that extend down and thrust back beyond the stern at 45 degree angles. These wings act as sloped armour to deflect impact taken by the bow. The thruster nacelles are mounted at the back of these wings, while the secondary gun ports, airlocks, docking tubes and deployment tube doors are all located alone the edge of the wings.
From stem to stern, the York-class Cruiser has a length of 707 meters, a beam of 190 meters and a height of 120.7 meters. With a mass of 1.17 million metric tonnes.
The main hull has a length of 568.5 meter, a width of 27.2 and a height of 66.4 meters.
The hull is protected by up to 1.6 meters of layered ablative ceramic composite armour plating. This armour serves as the inner layer of ship defenses. The armour is primarily designed to defend against directed energy weapons like lasers by boiling away when heated. The vaporised armour material scatters the DEW beam, rendering it ineffective.
A scaffold was built around the interior pressure hull, with sheets of ablative armor hung from the structure. Ships typically have multiple layers of armor separated by empty baffles, spaces often used for cargo storage. Cruisers, which lack the internal space to fit dedicated fighter hangars, store the shipboard fighter complement in the baffles.
The exterior hull is also lined with strips of ceramic as part of it's Defused Radiator Array, used to radiate the ship's passive heat build-up from everyday functions such as running thrusters, drives and other internal systems. Under thermographic imaging, this makes the ship appear striped, leading to the nickname "tiger stripes" or "war paint". Though, they are not as efficient as regular radiator panels, they are more durable. If damaged by enemy fire, the ship only loses a small portion of it's radiation capacity. In most cases, a vessels DRA alone allows it to cruise with no difficulty. Operations inside solar systems can cause problems.
During combat, the ship utilizes droplet heat sinks built into the hull itself. Filled with lithium, these sinks capture the titanic amounts of heat generated by weapons and thrusters during combat. Once filled to capacity, the lithium is sprayed out of nossels at the bow in the form of droplets, where they are cooled in the cold vacuum of space before being sucked back in at the stern. Droplet sinks can manage 10 to 100 times more heat than a DRA, but every time they are cycled through, a portion of the lithium coolent is lost to space. Limiting their use to only when necessary.
Shields
The Ships also feature a Cruiser-grade anti-bombardment kinetic barrier array linked to a Model 5 kinetic barrier shield generator. A reverse engineered improvement of a turian design.
Kinetic barriers consist of hundreds of tiny emitters spaced evenly across the outer hull. An object with mass traveling above a certain velocity will trigger the barrier's reflex system, generating a localised repulsive mass effect field around the point of impact, deflecting it.
This is not without risk, however. The emitters themselves can only repel objects up to a limit. Sufficiently massive objects traveling at a high enough velocity can pass through the barriers unimpeded. Additionally, the kinetic barrier generator takes power from the ship's mass effect drive. Even if the projectiles do not penetrate, consistent impacts can put strain on the generator, this strain in turn is carried back to the drive. To prevent potential drive failure, the drive is designed to temporarily shutdown power to the shields until the field stabilises once again. The sudden, abrupt shutdown of the generator causes all emitters to discharge residual energy build-up into the vacuum of space. Triggering the characteristics "shattering" effect.
This allows the ship to withstand impacts from ship-based weapons, but doesn't do anything against Directed Energy Weapons such as lasers.
The strength of the kinetic barrier depends on the size of the mass effect drive, the amount of element zero used and overall design of the drive and generator. The more powerful the mass effect fields the ship generates, the more powerful the shields can be. York-class Kinetic barriers are rated for the equivalent of 1.5 kt of kinetic energy per square centimeter. Estimated to be capable of shrugging off direct hits from a turian Cruiser.
Power and Propulsion
The ship's drive core is a Mk IV Orion Mass Effect Drive Core. This massive drive spanned across multiple decks. It's a modification of the older Mk III that incorporates turian design principles. The drive is powered by the ship's on board helium-3 nuclear fusion power plant, which delivers a powerful electrical current to a core of element zero, causing it to radiate large amounts of dark energy, which are captured by the mass effect field generators.
The Orion Drive is used to increase the power of on board weapons, generate kinetic barriers, reduce the mass of the ship, generate gravity, power inertial dampeners and more, but the most significant advantage the drive gives is the ability for faster than light space travel. The mass effect field generator generates a mass reducing field around the ship, lowering it's mass, while simultaneously raising the speed of light around it. Allowing for faster than light travel through conventional thrust without any negative effects. Ships accelerate for half the journey, befor flipping around and decelerating for the other half. This means that there is no consistent speed. A ship's FTL travel time is largely determined by the distance they travel. Longer distances allow for higher average velocities than shorter distances.
The Mk IV Orion Drive allows for a rate of approximately 65,000 km/s of acceleration and deceleration. Allowing for the ship to travel roughly 12.9 lightyears within a 24 hour period. However, due to static build-up of the drive core, the ship can not maintain FTL flight for longer than around 50 hours at a time. Limiting it's maximum FTL speed to around 56 lightyears every 2 days.
One downside however is that as the ship accelerates, the difference in light speed between the interior and exterior of the field causes a doppler shift. Objects outside the ship redshift, eventually only becoming visible to the ship's radio telescope antenna. As the ship goes faster, high-energy electromagnetic source such as x-rays, gamma rays, and eventually cosmic ray sources become visible, replacing stars with pulsars, the accretion disks of black holes, quasars and gamma ray bursts.
To an outside observer, the ship appears to be surrounded in a blue or purple aura as the light within the mass effect field is blueshifted into higher frequencies, making the field itself visible to the naked eye. The ship's radiation emissions are also compressed as a consequence. If within a field that allows light to move twice as fast, the ship produceed twice the emissions. If in a field that allowed for 200 times faster light speed, it's visible light is emitted as x-rays and gamma rays and the infrared heat of the hull is blueshifted up into the visible spectrum or higher.
As a result ship is almost completely blind during FTL flight, requiring a specially trained navigator to plot each FTL jump and instuct the helmsman on course corrections based on calculations provided by the ship's FTL plotter. If an object of significant enough mass is in the path of a planned FTL jump, a safety lock built into the drive core prevents the ship from accelerating above safe speeds. The safety lock was intentionally designed to be integral to the FTL warm-up process. Meaning that removing or tampering with the mechanism could cause critical damage to the drive core.
Ships also can not perform an FTL jump while under fire. Accelerating to FTL necessitates that a ship reduce it's mass to levels unsafe for combat. During large-scale combat, it's common practice for a losing fleet to sacrifice a portion of their forces to draw enemy fire while the rest of the fleet escapes. These ships would then attempt to escape combat at sublight speed, where they would jump to FTL as soon as they were out of range and rendezvous with the rest of the fleet.
Conventional thrust was provided by 2 aft and 2 fore antiproton drives witch inject antiprotons into a reaction chamber filled with hydrogen. The resulting matter-antimatter annihilation provides unmatched motive power. The drawback is fuel production. Antiprotons are produced one at a time in massive solar arrays orbiting energetic stars. Making them both expensive to produce and easy targets during wartime. The exhaust of an antiproton drive is measured in millions of degrees Celsius. Any ship caught behind it would melt like wax in a blowtorch.
Maneuvering is performed by an array of liquid oxygen/liquid hydrogen reaction control thrusters.
The ship features backup hydrogen-oxygen fuel cells to meet the minimum power requirements for the ship to function for a few hours, even after the fusion plant is taken offline.
Crew and Compliment
The standard crew size of a Berlin-class was 320 with facilities to accommodate upto 90 marines as required.
Emergency escape vehicles consist of 95 M-78 Hammer emergency evacuation pods, each equiped with their own emergency beacon, thruster module, heat shields, inertial dampeners and at least a week's rations for a crew of 8.
A York-class Cruiser includes two mass accelerator deployment tubes in the port wing that uses mass accelerator technology to accelerate and decelerate auxiliary craft with a redundant overhead accelerator claw that uses an electromagnetic catapult system to "throw" and "catch" auxiliary craft if necessary, linked to two shuttle bays carrying 2 UT-47 and later UT-47A Kodiak Drop Shuttles each as well as a hanger built into the baffles of the hull carrying a single squadron of 15 to 20 F-61 Trident Fighter/Interceptors.
Sensors and Communications
A York-class features a variety of active and passive sensors that give it a detailed visual of it's surroundings.
Passive sensors are used for long-range detection and include visual, thermographic and radio detectors that monitor the ship's surroundings at all times.
Active sensors are shorter range, but more accurate. They include ladar and radar that emit a "ping" of energy and "listen" for a return signal. Radar has a wider field of view than ladar, but ladar's higher resolution allows images of detected objects to be assembled.
Due to light-lag, passive sensor accuracy is reduced and active sensors don't work while the ship is traveling at FTL speeds.
Communication is achieved through tight-beam communication, which fires a communications laser at the nearest FTL comm bouy. Acting as mini, primative mass relays, these bouys use mass effect FTL corridors to transmit the data at superluminal speed along the comm bouy network. Depending on the distance between the sender and their nearest comm bouy, this method of communication is almost instantaneous, especially since military communications take high priority when it comes to communication bandwidth.
Armament
The York-class' primary armament consists of a number of mass accelerator cannons. Mass accelerators reduce the mass of a solid metal slug then accelerate it to high velocities using precisely controlled electromagnetic attraction and repulsion. Mass accelerators are able to achieve such high velocities that slugs had to be designed to deform on impact to increase the amount of energy transferred to the target. Otherwise it would pass right through, doing minimal damage.
The York-class' primary armament is a single SP-500 Mk III Heavy Mass Accelerator Cannon mounted along the spine of the ship. Accelerating a 20 kilograms slug of ferric titanium alloy at a velocity of 2 515 km/s every 2 seconds. Impacting with a force of 63.28 terajoules of kinetic energy. Equivalent to 15 kt of TNT or the bomb that dropped on Hiroshima. With an effective range from 38 km 23,400 km
Secondary weapons consist of a battery of 2 CS-145 Mk III Light Mass Accelerator chaser guns that support the main gun. Firing in two round burst of 20 kg of ferric titanium alloy each to a velocity of 730 km/s every 2 seconds. Impacting with 5.33 terajoules. Equivalent to 1.27 kt of TNT. With an effective range from 38 km to 6,800 km
And 20 batteries of BS-80 Mk III Light Mass Accelerator Broadside guns per side. Mounted on two decks of 10 and consisting of two guns each, each battery fires a two round burst of 20 kg of ferric titanium alloy at a velocity of 402.5 km/s every 2 seconds. Impacting with 1.62 terajoules of kinetic energy. Equivalent to 387 tonnes of TNT. With an effective range from 9 km to 3,700 km
As of 2182, York-class Cruisers included 12 M-83 Javelin torpedo tubes as a tertiary short-range weapon to compliment their point-defence network. Javelin torpedo are scaled up variants of the Fighter-launched disruptor torpedo. Like Disruptor torpedos, Javelins are equipped with element zero warheads that create random, unstable mass effect fields that warp space-time around them. In flight, they use mass increasing fields making them too massive to be blocked by kinetic barriers, but also making them sluggish and easy prey for point-defence systems. Javelins are fired in large numbers and in pairs, on converging trajectories, programmed to collide, just before impact, allowing the dark energy field emitted by the impact to resonate, magnifying the resulting warp effect.
Close-in defense against enemy missiles and fighters is the primary mission of the ship's General ARea Defense Integration Anti-Spacecraft Network (GARDIAN). Consisting of 110 anti-missile and anti-fighter laser turrets on the exterior hull. Since lasers move at the speed of light, they can not be dodged by anything traveling at superluminal speeds. At the start of combat, GARDIAN is 100% accurate. It's not necessarily 100% lethal, but it doesn't have to be. Damaged fighters have to break off attack for repairs. Defraction restricts GARDIAN's effective range to only a few kilometers. Fighters attack in swarms in an attempt to overwhelm the ship's GARDIAN defenses, the first few will be shot down, but as a battle progresses, overheating deteriorates both the accuracy and strength of the laser turrets.
Layout
The York-class had 13 decks.
The main gun ran through deck 3.
The Combat Deck was on Deck 5 and included a completely sealable Bridge, CIC and War Room. As well as the Captain's Cabin.
Deck 7, 8 and 9 were reserved almost exclusively for crew accommodations. Personnel facilities, R and R facilities, mess halls, barracks, training areas, medical bays, locker rooms, gyms.
The the broadsides guns and all the ship's ammunition stores were on Deck 10 and 11.
The aft section of the ship plays hosts to the power plant and mass effect drive. Accessed through the engineering deck on deck 12
Deck 13 contained the cargo hold. It also held the shuttle bay. The deployment tube on the port side linked to this deck as did the port and starboard docking tubes. The deployment tube is sealed by a heavy duty blast door as well as an environmental field made up of gas membrane held in place by mass effect fields that can be activated when the door is open to prevent the atmosphere from escaping, while still allowing vehicles to pass through unimpeded. The armoury was on this deck as well.
Ships of the Line
- SSV York C-68: Active 2160 - 2186
- SSV Budapest C-89: Active 2165 - 2192
- SSV Istanbul C-123: Active 2174 - 2186
- SSV Manila C-94: Active 2168 - 2186
- SSV Nairobi C-146: Active 2180 - 2186
- SSV Perugia C-82: Active 2164 - 2186
- SSV Zama C-111: Active 2171 - 2190
- SSV Tripoli C-99: Active 2170 - 2186